The invention relates to a device, a vehicle and a method for measuring a dimension between at least two points on surfaces.
Different methods and devices for the two-dimensional measurement of surfaces, such as e.g. vehicle surfaces, and for the three-dimensional measurement of objects, in particular of vehicles and mailing packages, are known.
DE 10 2012 005 966 A1 discloses a device for generating a two-dimensional representation of a three-dimensional body by using parallel light to project a shadow image of the three-dimensional body.
US 2004/0075847 A1 describes a sensor arrangement for determining the height of a vehicle, wherein the vehicle to be examined can be moved between two pillars in which light-emitting and light-receiving apparatuses are arranged in such a way that the vehicle or a respective section of the vehicle interrupts the light beams between these apparatuses, so that the height of the vehicle section can be ascertained on the basis of the interrupted light beams.
CH 701 106 A2 discloses a method and a device for measuring the spatial extent of an object, wherein the vertical profile and the floor contour of a vehicle can be determined by means of two measuring arrangements, one of which is embodied as a horizontally extending light barrier arrangement and the other of which has vertically extending laser beams with a camera as an associated sensor, when the vehicle is moved through both measuring arrangements during the measuring process.
U.S. Pat. No. 6,195,019 B1 explains a device for classifying vehicles and a toll system, wherein the device for classifying vehicles is arranged above a roadway on which vehicles are moving through a detection zone which is spanned by a laser scanner. The detection zone is spanned, on the one hand, longitudinally with respect to the direction of travel and, on the other hand, transversely with respect to the direction of travel.
JP 3110725 B2 discloses a two-dimensional measurement with a plurality of measurement sensors from above.
EP 0 828 990 B1 discloses a device for determining the dimensions of an object, in particular an object on a moving conveyor for package-sorting and -handling uses. The objects to be sensed move on a conveyor belt and are scanned from above by a laser scanner.
EP 0 858 055 A2 discloses a device and a method for measuring mail items, wherein the mail items are sensed by a camera, preferably from above, and the dimensions of the mail item are determined from the acquired images.
WO 03/025498 A1 discloses a system and a method for measuring the dimensions of moving packages, wherein light beams are directed onto the object and the reflections thereof are sensed using a light detector via a parabolic mirror, and the dimensions of the object in one dimension are determined from the sensed reflections.
DE 10 2013 103 897 A1 describes a camera module for line-by-line scanning of an object with at least one linear sensor and a lens for imaging the object on the sensor. The camera module has a plurality of line sensors which are arranged at a different distance from the lens so that image lines at a different distance from the lens are imaged on the respective line sensors.
An object of the invention is to provide a device and a method for a vehicle with which dimensions of an object or a plurality of objects or between objects in the surroundings of the vehicle can be measured precisely.
The present invention relates to a device for measuring a dimension between at least two points on at least one surface for a vehicle, comprising                at least one image-generating apparatus for scanning the surroundings of the vehicle,        a display apparatus for displaying the representation of the surroundings of the vehicle,        an input apparatus for defining at least two points as measuring points between which the dimensions are to be determined in the displayed representation,        at least one surroundings sensor for sensing the distance and the direction of the measuring points with respect to the vehicle, and        an evaluation apparatus for determining the dimension on the basis of the sensed distances and directions of the measuring points and for outputting the determined dimension.        
With the device for measuring a dimension between measuring points on at least one surface, such dimensions can be determined easily and precisely using the sensor system which is already present on the vehicle.
Precise measurement of two points on at least one surface in the surroundings of a vehicle permits e.g. the measurement of passages in width and/or height, such as e.g. in the case of garage entries or gate entries. It is also possible to quickly and easily measure passages between parking or stopping vehicles, so that a vehicle driver can decide whether he wishes to drive through this passage with his vehicle. Such situations occur, e.g. when trucks park in narrow roads and block a large part of the roadway. If it is desired to drive into warehouses or depots, it may be advantageous to measure the corresponding passages in advance. This applies, in particular, if the vehicle is a large truck which cannot be readily turned. Furthermore, goods which are to be transported can be measured. This is expedient, in particular, in conjunction with vehicles which serve to transport such goods, such as e.g. industrial trucks, tractors or the like. The sensed dimensions of the goods can be stored and used during further handling of the goods. For example, passages or storage locations can be measured with the method according to the invention and used to determine whether the goods can pass through or be stored there. Furthermore, pieces of baggage which are to be stowed in the vehicle can be measured in advance. The method is preferably developed in such a way that it checks whether the pieces of baggage can be accommodated in the loading space volume, and automatically determines proposals for the arrangement of the individual pieces of baggage in the loading space volume and displays them on the display apparatus. This makes it possible to load the vehicle both densely and according to regulations.
The device according to the invention can have here one or more image-generating apparatuses from the following group:                camera,        stereo camera,        thermal imaging camera,        3D time-of-flight camera,        laser scanner or rotation laser or lidar,        radar.        
Such image-generating apparatuses are often already present on vehicles.
In one preferred embodiment of the device according to the invention, one or more of the image-generating apparatuses are embodied in a rotatable or pivotable and/or zoomable fashion.
Such rotatability or pivotability makes it possible to define measuring points which it would otherwise not be possible to define when using rigidly arranged image-generating apparatuses. Making available zoomable image-generating apparatuses increases the accuracy of the definition of the measuring points in that a measuring point can be defined more precisely in the portion of the image which is enlarged by the zooming.
The device according to the invention can have one or more surroundings sensors from the following group:                stereo camera,        3D time-of-flight camera,        camera with auto-focusing apparatus or rangefinder,        optical distance-measuring device with line scan camera,        laser scanner or rotation laser or lidar,        radar,        ultrasonic sensor.        
In one preferred embodiment of the device according to the invention, one or more surroundings sensors are embodied in a rotatable or pivotable fashion.
Such rotatability or pivotability makes it possible to sense the distance and direction of measuring points which it would otherwise not be possible to sense when using rigidly arranged surroundings sensors.
In a further embodiment of the device according to the invention, the at least one image-generating apparatus also constitutes the surroundings sensor or both are integrated in one sensor (housing).
The resulting advantages are that the vehicle can be cost-effectively equipped with sensors, the sensors which are present on the vehicle are used efficiently and, in particular, by means of the integration, an offset between the image-generating apparatus and the surroundings sensor is avoided. Specifically in the case of non-identical or non-integrated sensors, such an offset can, under certain circumstances, lead to a situation in which although a point on a surface can be defined as a measuring point by means of the image-generating apparatus, this measuring point cannot be sensed owing to an obstacle which is located in a direct line between the surroundings sensor and the measuring point. This is avoided by constructing one and the same sensor as an image-generating apparatus and a surroundings sensors, since the viewing direction is identical in both cases.
In one preferred embodiment of the device according to the invention, a plurality of image-generating apparatuses and/or a plurality of surroundings sensors are arranged in such a way that they point in different directions with their viewing direction.
Such an arrangement makes it possible for the entire surroundings of the vehicle to be able to be sensed without moving the vehicle.
In a further preferred embodiment of the device according to the invention, one or more image-generating apparatuses and/or one or more surroundings sensors are arranged in such a way that they scan, from the vehicle, in particular from the underside or the underfloor of the vehicle, the ground region underneath the vehicle. In addition, these sensors can be embodied with a light source as a lighting apparatus.
The scanning of the ground region makes it possible also to define and sense points located under the vehicle as measuring points. In particular this is advantageous if marks which are provided on the ground are also to be included in a measurement. In this context, a light source permits here a definition or sensing of measuring points which it would not be possible to define or sense without illumination owing to the relatively dark light conditions underneath the bodywork of the vehicle.
In one preferred embodiment of the device according to the invention, one or more driving movement sensors are provided for detecting the movement of the vehicle. In this context, the evaluation apparatus is embodied in such a way that a measuring point is respectively scanned at different vehicle positions. In this context, the movement of the vehicle is also taken into account during the determination of the dimension.
This makes it possible, in the case of vehicles which have only a low number of image-generating apparatuses or surroundings sensors, also to define or sense measuring points which are not located in the field of vision of the respective sensor. The driving movement sensors are sensors which sense the movement or trajectory of the roadway. Examples of these are specified in the following group:
Wheel rotation sensor, steering angle sensor, acceleration sensor, speedometer, rev counter in conjunction with a transmission sensor, inclination sensor, spring travel sensor or chassis sensor.
According to a further aspect of the present invention, a method is provided for measuring a dimension between at least two points of at least one surface for a vehicle, in particular having the device explained above, which method comprises the steps                scanning and generating a representation of the surroundings of the vehicle,        displaying the representation of the surroundings of the vehicle,        defining at least two points as measuring points between which the dimensions are to be determined in the displayed representation,        sensing the distance and the direction of the measuring points with respect to the vehicle,        determining the dimension on the basis of the sensed distances and directions of the measuring points and outputting the determined dimension.        
In a further embodiment of the method according to the invention, the curvature of the surface between the measuring points is detected by sensing the distance and the direction of further points which lie on a virtual line or, if appropriate, projected line on the at least one surface between the measuring points from the image-generating apparatus and/or from the surroundings sensor. The curvature of the surface which is determined as a result is also taken into account during the determination of the dimension.
As a result, the three-dimensional form of surfaces is also included during the determination of a dimension.
In a further embodiment of the method according to the invention, a multiplicity of measuring points is scanned. A plan or a 3D model of the surroundings of the vehicle is produced from the data determined by means of the scanning.
As a result, such a plan or such a 3D model can be produced easily and efficiently with the sensor system present on the vehicle.
In this context, the plan can comprise a floor plan and/or an elevation.
In a further embodiment of the method according to the invention, objects which have been predetermined from sensed data are filtered out autonomously.
As a result of the autonomous filtering out, it is possible, on the one hand, to determine objects which are of interest for measurement and to offer them for measurement, and, on the other hand, the objects which are unsuitable for measurement can be detected, with the result that they are not offered for measurement. In particular, moving objects are unsuitable for measurement, since the measuring points cannot be defined or scanned without a relatively large deviation.
In a further embodiment of the method according to the invention, one or more of the following types of predetermined objects are sensed automatically by means of image analysis:                fence,        boundary stone,        wall,        ceiling of a building,        floor,        outer or inner edge of a building,        roadway,        leveling rod,        beacon,        post,        passage,        entry,        industrial truck,        transportation material,        transportation pallet,        storage rack,        piece of baggage,        vehicle.        
As a result, the determination of dimensions or the production of plans can be carried out more quickly and efficiently.
In one advantageous embodiment of the method according to the invention, the movement of the vehicle is detected when the vehicle is moved between the sensing of the distance and the directed two measuring points. This detected movement is also taken into account during the determination of the dimension.
As a result it becomes possible to determine dimensions between measuring points and surfaces with a sensor system on the vehicle which cannot sense all the regions in the surroundings of the vehicle. Likewise, a measurement can then also be carried out when the direct view of an image-generating apparatus and/or of a surroundings sensor of a measuring point is impeded by an obstacle, for example by an object in the respective line of sight thereof. The measurement can then often be carried out by moving the vehicle between the sensing of the distance and the direction of one measuring point and the sensing of the distance and the direction of a further measuring point despite the impeding object.
In a further embodiment of the method according to the invention, the vehicle moves autonomously between the sensing of the distance and the direction of the measuring points.
By means of an autonomous movement of the vehicle, the automatic measurement of even relatively large external spaces or internal spaces is made possible. As a result, in particular plans can be produced more efficiently.
In one advantageous refinement of the method according to the invention, after the definition of a measuring point it is checked whether the measuring point can be sensed with one of the surroundings sensors.
If an image-generating apparatus and a surroundings sensor on a vehicle have an offset with respect to one another because the two are not identical sensors or are not integrated in one and the same sensor (housing), then a situation may arise in which although a measuring point can be defined on a surface in the representation of the surroundings of the vehicle which is produced by the image-generating apparatus, the surroundings sensor cannot sense the distance and the direction to the measuring point owing to an impeding object or owing to its orientation. Such checking makes it possible to display a message to the vehicle occupant who is carrying out the measurement that a defined measuring point cannot be sensed. Additionally or alternatively, in such a case a trajectory can be calculated which is displayed either for the vehicle driver to be traveled along manually, or which is traveled along autonomously by the vehicle, in order to permit one of the surroundings sensors of the vehicle nevertheless to sense the measuring point. When such a trajectory is generated, other measuring points in the surroundings of the vehicle are advantageously sensed and also included to avoid collisions during the calculation of the trajectory. In order to be able to carry out a calculation of such a trajectory more precisely, further systems or apparatuses which are present on the vehicle or the data thereof can also be included, such as for example a distance-measuring apparatus.
Dimensions can be 3D coordinates, distances, angles, diameters, radii, etc.
According to a further aspect of the present invention, a vehicle is provided which has one of the devices according to the invention explained above, wherein the device can, in particular, execute one of the methods according to the invention explained above.
The vehicle according to the invention can have a four-wheel drive and/or at least a ground clearance of at least 15 cm and preferably of at least 20 cm.
By means of such a four-wheel drive and/or such a minimum ground clearance it is possible to measure measuring points even under off-road conditions or away from paved roadways.
The invention will be explained in more detail below by way of example with reference to the drawings, in which:
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.